<!DOCTYPE html>
<style>
  .curtain {
    position: fixed;
    left: 0px;
    top: 0px;
    right: 0px;
    bottom: 0px;
    width: 100%;
    height: 100%;
    z-index: -1;
    background-color: #048;
  }
</style>
<!-- Confound naive hit testing by appearing to cover the whole screen,
     while actually having a negative z-index. -->
<div role="group" class="curtain">
  <div role="group" class="curtain">
  </div>
</div>
<div>
  <div style="width: 5px; height: 5px; background: lightgray; display: inline-block; margin: 10px" aria-label="rect1"></div>
  <div style="width: 5px; height: 5px; background: lightgray; display: inline-block; margin: 10px" aria-label="rect2"></div>
  <div style="width: 5px; height: 5px; background: lightgray; display: inline-block; margin: 10px" aria-label="rect3"></div>
  <div style="width: 5px; height: 5px; background: lightgray; display: inline-block; margin: 10px" aria-label="rect4"></div>
  <div style="width: 5px; height: 5px; background: lightgray; display: inline-block; margin: 10px" aria-label="rect5"></div>
</div>
<iframe src="simple_rectangles_iframe.html" style="width: 200px; height: 50px; margin: 20px"></iframe>
<!-- Confound naive hit testing by appearing to cover the whole screen -->
<div role="group" class="curtain">
  <div role="group" class="curtain">
  </div>
</div>
